One patent document discloses an example of displaying actions, daily activities, rest and sleep as a band graph in a system for collecting vital data of a user. Moreover, another patent document discloses an example in which sleep and awaking are displayed as a band graph in a sleep state evaluation apparatus. In both cases, the user can distinguish a sleep period and a period other than the sleep period, however, the user cannot know information other than information for each time band and length of the time band.
Moreover, another patent document discloses a band graph representing a sleep depth by shading of colors as a system for evaluating the sleep states. In this example, the user cannot know a relationship between sleep and activities.
Patent Document 1: Japanese Laid-open Patent Publication No. 2012-235920
Patent Document 2: Japanese Laid-open Patent Publication No. 2013-045336
Patent Document 3: Japanese Laid-open Patent Publication No. 2010-148829
Therefore, there is no technique for enabling the user to chronologically grasp a relation between a depth of sleep and an intensity of an activity.